multiple pregnancy

Multiple Pregnancy

Definition

Multiple pregnancy is a pregnancy where more than one fetus develops simultaneously in the womb.

Description

Twins happen naturally about one in every 100 births. There are two types of twinning—identical and fraternal. Identical twins represent the splitting of a single fertilized zygote (union of two gametes or male/female sex cells that produce a developing fetus) into two separate individuals. They usually, but not always, have identical genes. When they do not separate completely, the result is Siamese (or conjoined) twins. Fraternal twins are three times as common as identical twins. They occur when two eggs are fertilized by separate sperm. Each has a different selection of its parents' genes. The natural incidence of multiple pregnancy has been upset by advances in fertility treatments, resulting in higher rates of multiple births in the United States. All these children are fraternal; they each arose from a separate egg and a separate sperm. Cloning produces identical twins.

The human female is designed to release one egg every menstrual cycle. A hormone called progesterone, released by the first egg to be produced, prevents any other egg from maturing during that cycle. When this control fails, fertilization of more than one egg is possible. Fertility drugs inhibit these controls, allowing multiple pregnancy to occur. Multiple pregnancy is more difficult and poses more health risks than single pregnancy. Premature birth is greater with each additional fetus.

The problem with multiple births is that there is only so much room in even the most accommodating womb (uterus). Babies need to reach a certain size and gestational age before they can survive outside the uterus. Prematurity is the constant threat of multiple pregnancies. Twins have five times the death rate of single births. Triplets and higher die even more often. The principle threat of prematurity is that the lungs are not fully developed. A disease called hyaline membrane disease afflicts premature infants. Their lungs do not stay open after their first breath because they lack a chemical called surfactant. Survival of premature infants was greatly improved when surfactant was finally synthesized in a form that could be of benefit to premature babies. Tiny babies also have trouble regulating their body temperature.

Causes and symptoms

Fertility drugs prevent the normal process of single ovulation by permitting more than one egg at a time to mature and ovulate (move from the ovary to the uterus in anticipation of fertilization). This happens naturally to produce fraternal twins. The first drug to accomplish this was clomiphene. Subsequently, two natural hormones—follicle stimulating hormone and chorionic gonadotrophin—were developed and used.

Diagnosis

Multiple pregnancies cause the uterus to grow faster than usual. Obstetricians can detect this unusually rapid growth as the pregnancy progresses. Before birth, an ultrasound will also detect multiple babies in the uterus. After birth, physical appearance or a careful examination of the placenta and amniotic membranes will usually reveal whether the babies were in the same water bag or separate ones. One bag means identical twins.

A multiple pregnancy almost always means increased monitoring and surveillance for complications. This often means more frequent visits to the healthcare provider, serial ultrasounds to make sure that the babies are growing adequately, amniocentesis to check for lung development, and close monitoring for preterm labor.

Treatment

Mothers may be put on bedrest during a multiple pregnancy, in order to try to try to prevent pre-term labor and delivery. If preterm labor is impossible to control at home, the mother may be hospitalized, and medication may be used to attempt to control contractions and dilatation of the cervix. Multiple pregnancies more often end in cesarean deliveries than singleton pregnancies.

Babies from multiple pregnancies are often born early, and may require longer-than-normal hospitalization. The babies may need assistance with breathing, careful control of body temperature within an incubator, and surveillance for other complications that frequently beset pre-term babies. While premature babies are fragile in many other ways, modern methods of intensive care have successfully stabilized babies as small as one pound.

Alternative treatment

There are no specific treatments to alleviate medical difficulties caused by multiple pregnancies, however there are supportive measures that may help both mother and children recover from the birthing process. There are treatments to encourage breast milk production and to combat postpartum difficulties. Various homeopathic remedies and massage can be helpful to both mother and children during the early adjustment period after birth.

Prognosis

With modern medical advances and excellent prenatal care, many multiple pregnancies reach fruition without difficulties. If the babies are born prematurely, immediate medical care increases the chance of survival without any complications.

Resources

Periodicals

pregnancy

[preg´nan-se]

the condition of having a developing embryo or fetus in the body, after union of an oocyte (ovum) and spermatozoon. The average gestation period for a human pregnancy is 10 lunar months (280 days) from the first day of the last menstrual period.

Conception. Once a month an ovum (secondary oocyte) matures in one of the ovaries and travels down the nearby fallopian tube to the uterus; this process is called ovulation. At Fertilization, which must take place within a day or two of ovulation, one of the spermatozoa unites with the ovum to form a zygote. The zygote then implants itself in the wall of the uterus, which is richly supplied with blood, and begins to grow. (See also reproduction.)

Signs of Pregnancy. Usually the first indication of pregnancy is a missed menstrual period. Unless the period is more than 10 days late, however, this is not a definite indication, since many factors, including a strong fear of pregnancy, can delay menstruation. Nausea, or morning sickness, usually begins in the fifth or sixth week of pregnancy. About 4 weeks after conception, changes in the breasts become noticeable: there may be a tingling sensation in the breasts, the nipples enlarge, and the areolae (dark areas around nipples) may become darker. Frequent urination, another early sign, is the result of expansion of the uterus, which presses on the bladder.

Other signs of pregnancy include softening of the cervix and filling of the cervical canal with a plug of mucus. Early in labor this plug is expelled and there is slight bleeding; expulsion of the mucous plug is known as show and indicates the beginning of cervical dilatation. chadwick's sign of pregnancy refers to a bluish color of the vagina which is a result of increased blood supply to the area.

When the abdominal wall becomes stretched there may be a breaking down of elastic tissues, resulting in depressed areas in the skin which are smooth and reddened. These markings are called striae gravidarum. In subsequent pregnancies the old striae appear as whitish streaks and frequently do not disappear completely.

There are several fairly accurate laboratory tests for pregnancy; all are designed to detect human chorionic gonadotropin (hCG), a hormone produced by living chorionic placental tissue and evident in the blood and urine of pregnant women. See also pregnancy tests.

Growth of the Fetus. The average pregnancy lasts about 280 days, or 40 weeks, from the date of conception to childbirth. Since the exact date of conception usually is not known, the estimated date of delivery can be calculated using nägele's rule. This is approximate, since pregnancy may be shorter than the average or can last as long as 300 days. (For stages of growth of the fetus, see fetus.)

Care of the Fetus. A host of influences can adversely affect the growth and development of the fetus and his or her chances for survival and good health after birth. The diet of the mother should be nutritious and well-balanced so that the fetus receives the necessary food elements for development and maturity of body structures. It is especially important that the mother receive adequate protein in her diet, because a protein deficiency can hamper fetal intellectual development. Supplemental iron and vitamins usually are recommended during pregnancy.

There is now less emphasis on severe restriction of the mother's dietary intake to maintain a limited weight gain. The average gain is about 28 lb during pregnancy, and either starvation diets or forced feedings can be unhealthy for the mother and hazardous for the fetus. Ideally, the mother should achieve normal weight before she becomes pregnant because obesity increases the possibility of eclampsia and other serious complications of pregnancy. Mothers who are underweight are more likely to deliver immature babies who, by virtue of their physiologic immaturity, are more likely to suffer from birth defects, hyaline membrane disease, and other developmental disorders of the newborn.

Other factors affecting the fetus include certain drugs taken by the mother during pregnancy. A well-known example is thalidomide, which inhibits the growth of the extremities of the fetus, resulting in gross deformities. Many drugs, including prescription as well as nonprescription medications, are now believed to be capable of causing fetal abnormalities. In addition, consumption of alcohol during pregnancy may result in fetal alcohol syndrome. Most health care providers recommend that all drugs be avoided during pregnancy except those essential to the control of disease in the mother.

Diseases that increase the risk of obstetrical complications include diabetes, heart disease, hypertension, kidney disease, and anemia. rubella (German measles) can be responsible for many types of birth defects, particularly if the mother contracts it in the first 3 months of pregnancy. Sexually transmitted diseases can have tragic effects on the baby, even though the symptoms in the mother are minor at the time of pregnancy. syphilis is particularly dangerous because it is one of the few diseases that can be transmitted to the fetus in utero. The baby is either stillborn or born infected, and rarely escapes physical or mental defects or both. Successful treatment of the mother before the fifth month of pregnancy will prevent infection in the infant.

During the birth process the infant may be infected with gonorrhea as it passes through the birth canal. Gonorrheal infection of the eyes can cause blindness. herpes simplex Type II involving the genitals of the mother can also be transmitted to the infant at birth. The mortality and morbidity rates for such infected infants are high.

The age of the mother is also an important factor in the well-being of the fetus. The mortality and morbidity rate for infants born of mothers below age 15 and above 40 are higher than for those of mothers between these ages.

Recently developed tests to monitor fetal health have taken much of the guesswork out of predicting the chances of survival and health status of the fetus after birth. Such tests and evaluation techniques include amniocentesis, chemical and hormonal assays, biophysical profiles, testing for alpha-fetoprotein, ultrasound examinations, electronic surveillance of fetal vital signs and reaction to uterine contractions, and analyses of the infant's blood during labor.

Prenatal Care. The care of the mother during her entire pregnancy is important to her well-being and that of the fetus she is carrying. It will help provide ease and safety during pregnancy and childbirth. The health care provider learns about the patient's physical condition and medical history, and can detect possible complications before they become serious.

On the first prenatal visit the patient's medical history is taken in considerable detail, including any diseases or operations she has had, the course of previous pregnancies, if any, and whether there is a family history of multiple births or of diabetes mellitus or other chronic diseases. The first visit also includes a thorough physical examination and measurement of the pelvis. Blood samples are taken for screening for rubella and sexually transmitted diseases such as syphilis, hepatitis B, chlamydiosis, infection by the human immunodeficiency virus, and other conditions. A complete blood count is also needed. Urine is tested for albumin and sugar and examined microscopically. On subsequent visits the patient brings a urine specimen, collected upon arising that morning, to be tested for albumin and glucose. At each prenatal visit her blood pressure is taken and recorded and she is weighed. In the second trimester, when the uterus becomes an abdominal organ, the height of the fundus is measured at each visit. After the sixth month a rule such as mcdonald's rule can be applied to assess fetal growth.

Patients who are considered high-risk mothers usually are sent to a specialist and the infant is delivered at a regional hospital where sophisticated monitoring equipment and laboratory tests are available, and specially trained personnel can attend to the needs of the mother and her infant.

Discomforts and Complications.morning sickness usually appears in the early months of pregnancy and rarely lasts beyond the third month. Often it requires no treatment or can be relieved by such simple measures as eating dry crackers and tea before rising. Indigestion and heartburn are best prevented by avoiding foods that are difficult to digest, such as cucumbers, cabbage, cauliflower, spinach, onions, and rich foods. Constipation usually can be corrected by diet or a mild laxative; strong laxatives should not be used unless prescribed by the health care provider.

A visit to a dentist early in pregnancy is a good idea to forestall any possibility of infection arising from tooth decay. Pregnancy does not encourage tooth decay. Hemorrhoids sometimes occur in pregnancy because of pressure from the enlarged uterus on the veins in the rectum. The health care provider should be consulted for treatment. varicose veins also result from pressure of the uterus, which restricts the flow of blood from the legs and feet. Lying flat with the feet raised on a pillow several times a day will help relieve swelling and pain in the legs. In more difficult cases the health care provider may prescribe an elastic bandage or support stockings.

Backache during pregnancy is caused by the heavy abdomen pulling on muscles that are not normally used, and can be relieved by rest, sensible shoes, and good posture. Swelling of the feet and ankles usually is relieved by rest and by remaining off the feet for a day or two. If the swelling does not disappear, the health care provider should be informed since it may be an indication of a more serious complication.

Shortness of breath is common in the later stages of pregnancy. If at any time it becomes so extreme that the woman cannot climb a short flight of stairs without discomfort, the health care provider should be consulted. If a mild shortness of breath interferes with sleep, lying in a half-sitting position, supported by several pillows, may help.

ectopic pregnancy pregnancy in which the fertilized ovum becomes implanted outside the uterus instead of in the wall of the uterus; this is almost always in a fallopian tube (tubal pregnancy), although occasionally the ovum develops in the abdominal cavity, ovary, or cervix uteri. Called also extrauterine pregnancy.

In a tubal pregnancy a spontaneous abortion may occur, but more often the fetus will grow to a size large enough to rupture the tube. This is an emergency situation requiring immediate treatment. The symptoms of such a tubal rupture are vaginal bleeding and severe pain in one side of the abdomen. Prompt surgery is necessary to remove the damaged tube and the fetus, and to stop the bleeding. Fortunately, the removal of one tube usually leaves the other one intact, so that future pregnancy is possible. Patients who are Rh-negative should be given Rh0 (D) immune globulin (RhoGAM) after ectopic pregnancy for isoimmunization protection in future pregnancies.

Ectopic pregnancy. The fallopian tube is the most common site for ectopic pregnancies but they can also occur on the ovary or the peritoneal surface of the abdominal cavity. From Damjanov, 2000.

surrogate pregnancy one in which a woman other than the female partner is artificially impregnated with the male partner's sperm. The resultant child represents only the male of the marital unit, and may be adopted by the female.

pregnancy tests procedures for early determination of pregnancy. By the first missed menstrual period or shortly thereafter, human chorionic gonadotropin (hCG), a hormone secreted by the placenta, is present in the blood and urine of a pregnant woman. It was formerly determined by bioassay in which a urine or serum specimen was injected into a laboratory animal and the response of ovarian tissue was noted. All testing now uses immunologic techniques based on antigen-antibody binding between hCG and anti-hCG antibody. There are several commercial kits available (see early pregnancy tests), based on the agglutination of hCG-coated latex particles by anti-hCG serum, which is inhibited if the urine specimen added to the serum contains hCG. Clinical laboratories generally use radioimmunoassay or radioreceptor assay to determine serum hCG levels. These methods are more accurate and less likely to produce false-positive results.

Multiple pregnancy rates in the UAE have increased in recent years which is mainly attributed to an increase in maternal age and an increase in using assisted reproduction techniques, that is more women are seeking in-vitro fertilization (IVF) and other assisted reproductive techniques (ARTs).

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